Wednesday, October 14, 2015

Explanation: Is there anything interesting to see in the direction opposite the Sun? One night last month, there were quite a few things. First, the red-glowing orb on the lower right of the original image is the full moon, darkened and reddened because it has entered Earth's shadow. Beyond Earth's cone of darkness are backscattering dust particles orbiting the Sun that standout with a diffuse glow called the gegenschein, visible as a faint band rising from the central horizon and passing behind the Moon. A nearly horizontal stripe of green airglow is also discernable just above the horizon, partly blocked by blowing orange sand.

Wednesday, August 5, 2015

This animation features actual satellite images of the far side of the moon, illuminated by the sun, as it crosses between the DSCOVR spacecraft's Earth Polychromatic Imaging Camera (EPIC) and telescope, and the Earth - one million miles away [NASA/Goddard].

Friday, June 26, 2015

Artist's conception of the lunar dust exosphere surrounding the moon. The color represents the amount of material ejected from the surface, showing a peak in the apex direction. A haze of dust is shown around the moon. Gray faded circles are overlaid on the lunar surface to represent the random nature of the primary impactors. An artist's conception of the LADEE orbital inclination is also shown [UC Boulder/Daniel Morgan/Jamey Szalay].

Darryl Waller

Sharon Lozano

NASA Ames

New science results from NASA’s LADEE mission (Lunar Atmosphere and Dust Environment Explorer) indicate the Moon is regularly engulfed in a permanent, but lopsided and transitory, dust cloud increasing in density during encounters with cometary debris, like those producing the Geminids, according to a new study led by University of Colorado Boulder.

"Knowledge about the dusty environments in space has practical applications," said CU-Boulder physics Professor Mihály Horányi. "Knowing where the dust is and where it is headed in the solar system could help mitigate hazards for future human exploration, including dust particles damaging spacecraft or harming astronauts."

The cloud was discovered using data from a detector on board LADEE called the Lunar Dust Experiment (LDEX) designed and built by CU-Boulder. LDEX charted more than 140,000 impacts during the six-month survey launched in September 2013. NASA’s Ames Research Center in Moffett Field, California was responsible for spacecraft design, development, testing and mission operations.

“The LDEX team has been painstakingly analyzing their data since the LADEE mission ended on April 18, 2014,” said LADEE project scientist at Ames, Rick Elphic. “Their results answer one of the big LADEE science questions: is there a dust component to the tenuous lunar atmosphere? And if so, why is it there?”

According to Horányi, the cloud is primarily made up of tiny dust grains kicked up from the moon’s surface by the impact of high-speed, interplanetary dust particles. A single dust particle from a comet striking the moon’s surface lofts thousands of smaller dust specks into the airless environment, and the lunar cloud is maintained by this sometimes predictable process of regolith "gardening."

“Identifying this permanent dust cloud engulfing the moon was a nice gift from this mission,” said Horányi, the principal investigator for the LDEX instrument and lead author of the study. “We can carry these findings over to studies of other airless bodies, like the moons of other planets and the asteroids.”

A paper on the subject appears in the June 17 issue of Nature. Co-authors Jamey Szalay, Sascha Kempf, Eberhard Grun and Zoltan Sternovsky from CU-Boulder, Juergen Schmidt from the University Oulu in Finland, and Ralf Srama from the University of Stuttgart in Germany.

The first hints of a cloud of dust around the moon came in the late 1960s when cameras functioning overnight aboard the unmanned moon lander Surveyor 7 captured bright glow hours ahead of lunar sunrise. Not long after astronauts in lunar orbit described a significant glow above the lunar surface when approaching sunrise, phenomenon brighter than the sun by itself should have been able to produce over a body with only a trace, essentially non-existent, atmosphere.

Because these new findings do not square with the Apollo reports of a thicker, higher dust cloud, conditions back then may have been somewhat different. The dust on the moon -- which is dark and sticky and regularly dirtied the suits of moonwalking astronauts -- was created over several billion years as interplanetary dust particles incessantly pounded the rocky lunar surface.

Many of the cometary dust particles impacting lunar surface are traveling at thousands of miles per hour in a retrograde, or counterclockwise orbit around the sun, the opposite orbital direction of the solar system’s planets. This causes high-speed, near head-on collisions with the dust particles and the moon’s leading surface as the Earth-moon system travel together around the sun.

Monday, June 22, 2015

This is perhaps the premier conference on space resource utilization, space mining, granular mechanics in space, etc. Springtime in Orlando figuring out how to extend human civilization into the solar system - what could be better?

With a low-cost launch, they now have a lander with the potential for precision landings driven by new system on a chip (SOC) technologies developed by Nvidia with help from General Electric.

Astrobotic knows that space and robotics are not that easy, but at a recent Nvidia-sponsored technology conference, the company’s engineers were presenting technologies that it argues could ease and accelerate the path to the Moon.

And the company is offering anyone — including their X-PRIZE competitors — a ride to the Moon. Safely on the surface they propose a civilized Mad Max road race to the finish line – 500 meters away – the winner taking the $20 million grand prize.

To make their moon mission a reality, the company is blending an interesting mix of old and new into their lander design, the Griffin Lander.

The new includes the Nvidia Tegra K1 chip used initially in its Jetson dev kit. The old is none other than General Electric designing the custom boards based on Tegra K1 and low-cost computer boards they hope will be recognized as a better, cheaper, alternative to existing radiation-hardened electronics costing millions. The Nvidia dev kit costs little more than $300.

Tapping their own wiz-kids from Carnegie-Mellon, Astrobotics is using laser-guided imagery that was developed to compete for the DARPA Grand Challenge for autonomous vehicles. For Astrobotic, the convergence of all of this tech is designed to get them beyond just the Google Lunar X-PRIZE but much more.

Monday, March 16, 2015

North is to the left, west below in this animation showing what is almost certainly an impact and its plume (right) on the lunar surface in Mare Nubium, on the morning side of the terminator, February 26 [Marco Iten/GLR Group].

Marco Iten

Raffaello Lena

Stefano Sposetti

Geological Lunar Research Group

Report from Selenology Today Preliminary Report 2015:Abstract: We report the detection of an interesting luminous event most probably generated by a meteoroidal impact on the lunar surface occurred at 21h 35m 22.871s ± 0.010s UT, the 26 February 2015. The position of the flash was along the terminator at selenographic coordinates 7.9° ± 0.6° W; 26.1° ± 1.6° S. The brightness of the flash 0.16 s after the initial detection was +8.0 magV. After the main lightdrop a successive residual diffuse light lasted for several seconds.

Under the assumption of a meteoroidal impact we argue that this post luminous event and its ever growing dimensions was likely caused by the sunlight reflection on ejected materials released by the impact. Thus, future high resolution orbital data, e.g., from LRO spacecraft (NAC images) could allow the detection of this crater. Because this event was captured only by one observer, we checked for satellite glints and evaluated the likelihood of a meteor hitting head on our atmosphere.

1. Instruments observing methods, location The detection was made by Marco Iten from Gordola, Switzerland. He used a 125 mm refractor with a focal length of 800 mm. He also used an 8bit Watec 902H2 Ultimate videocamera working in CCIR mode with these settings: Gamma = OFF; BLC = OFF; AGC = LO. A GPS time inserter (KIWIOSD) printed the Universal Time with millisecond precision in the video frames. The software Virtualdub was used to record the AVI file in a hard disk, with Huffyuv video compressor.

Iten's observatory is located at:

Lat: 46d 10m 44s North

Long: 08h 52m 29s East

Alt: 215 m

Stefano Sposetti was simultaneously filming the Moon from its observatory, but the lunar region where the flash occurred was outside its field of view.

Here some informations about the Moon at the detection instant, accordingly to sky simulator software TheSkySix ®.

Equatorial 2000:

RA: 05h 23m 27s

Dec: +17°44'32"

Horizon:

Azim: 250°41'00"

Alt: +41°21'54"

Phase (%): 62.19

Air mass: 1.51

Moon angular diameter: 0°30'33"

Moon distance (km): 3.910 E+05

Artificial satellites: We checked for artificial satellites in the field of view using the website http://www.calsky.com.

The satellite Molniya 340 (21196 1991022A) was at an angular distance of 32 arcmin from the Moon center at the time of the detection. We exclude that this satellite caused the detected flash in Iten's avi.

Luminosity evolution

From the very beginning of the event to +0.14 s (the first seven 20 msfieldintegrationtime) the intensity of all, or at least some, of the pixels is saturated.

The angular sampling of the individual images composing the video file is 2.4 arcsec/pixel. We noticed a non circular increase of the light source, therefore we calculated its augmentation with respect to x and y components (Fig. 4). The apparent radius of the Moon is almost parallel to the x axis.

At the location of the event, the absolute sampling of the image (normal to the moon radius, ie. of the y axis), is 4.5 km/pixel (on the lunar surface). The absolute sampling of the image in the x direction has to be multiplied by a factor 1.24 (= 1/sin 54°) i.e. to 5.6 km/pixel.

At time +6.62 s the x and y diameter of the external border of the “lightcloud” are about 10 pixels and 12 pixels, respectively. This translates to an effective length on the lunar surface of 54 km and 56 km.

If we assume that the increase of the light source is due to the ejected materials elevated from the bottom and if this cloud has a circular shape relative to a tangent plane to the surface, then the mean speed of the augmenting radius is about 4 km/s.

The increase of the lightsource is showed in figure 5 and in some animations we posted at

A visual inspection of the “lightcloud” in the video animation confirms that the expansion lasted until +10s. This translates to a circular effective diameter of about 80 km.

Selenographic Lunar coordinates

The coordinates of the detected flash are determined to:

Long: 7.9° ± 0.6° West

Lat: 26.1° ± 1.6° South

in Mare Nubium, near the crater Lippershey P, located to the south of Birt crater.

The analyzed image displays lunar features that were of very low contrast on the dark limb of the imaged lunar surface. Thus, after alignment with the edge of the lunar disk, computation of the libration, and overlay of the rotated Moon's surface matching the image generated by a simulated image obtained with the LOLA DEM, a coordinate map was superimposed. This procedure was performed using the LTVT software package by Mosher and Bondo (2006). Generating an elevation map of a part of the lunar surface requires its three dimensional (3D) reconstruction. Recently, a global lunar digital elevation map (DEM) obtained with the Lunar Orbiter Laser Altimeter (LOLA) instrument on the Lunar Reconnaissance Orbiter (LRO) spacecraft has been released. It has a lateral resolution of 1/64 degrees or about 500 m in the equatorial regions of the Moon http://pdsgeosciences.wustl.edu/missions/lro/lola.htm

Hence, the rendered image obtained using LTVT and the LOLA DEM, assuming the same illumination conditions and librations of the observing session, was saturated allowing a close comparison with the appearance of the saturated terminator as seen in Fig. 2, and further refined considering the uncertainty comparing the map with the WAC imagery of the Lunar Reconnaissance Orbiter.

We report this luminous event as an “unconfirmed lunar flash” being considered an impact candidate. In fact, considering that the event was only recorded by one video camera the possibility of a meteor "headon" producing the recorded light cannot be ruled out. Therefore we tried to evaluate the post spread of light as being emitted by the ionization of the high altitude gases of our atmosphere. Sometimes luminous meteors leave luminous trails and in this chapter we try to discard this possibility. We got the direction of the winds and their speed using the website

In this study, and under the assumption of an impact event, the same formalism and equations as in the works by Bellot Rubio et al. (2000), Ortiz et al. (2000), Ortiz et al. (2002), and Carbognani (2000) was followed, including the kinetic energy that is translated into impactor mass assuming a typical sporadic impactor speed. According to the statistics of a large meteoroid orbit database (Steel, 1996) this speed is approximately 20.2 km s1 on Earth and 16.9 km s1 on the Moon, after correcting for the different escape velocities of the Earth and the Moon.

Moreover a short routine provided by Melosh and Beyer (1999) was used to evaluate the scaling equations to determine the diameter of a crater given details on the nature of the projectile, conditions of impact, and state of the target. The transient crater diameter is evaluated by three independent methods, yield scaling, piscaling and Gault's semiempirical relations supplemented by rules on how crater size depends on gravity and angle of impact.

The parameters used in the calculation are the projectile density, the target density (2700 kg m3), the impact velocity (16.9 km s1), the peak brightness (5.5 MagV) and the duration of 0.22 seconds. Using the luminous efficiency η = 2 x 103 (the nominal value determined from Leonid impact flashes, e.g., Bellot Rubio et al., 2000; Ortiz et al., 2002), the mass of the impactor would be 1.1 kg. Based on the above data and assuming a spherical projectile, the diameter of the impactor was inferred to be approximately between 9 and about 20 cm considering a bulk density ranging between 0.3 g cm3 (soft cometary material) to 3.7 g cm3 (corresponding to ordinary chondrites). This impactor would strike the target with an impact energy of 1.7 x 108 Joules (4.0 x 108 MegaTons). If the meteoroid is associated as a sporadic source, the impact angle is unknown. We have used the most likely angle of 45° to estimate the size of the crater produced by the impact.

Using the Piscaled law for transient craters, the final crater would be a simple crater with a rim to rim diameter of about 1520 m.

However, considering that the brightness of the detected flash was saturated and the described presence of a luminous post event, the values inferred for the mass of the probable impactor and the crater size originated by the impact could be considerably higher.

Future high resolution orbital data, e.g., from LRO spacecraft (NAC images) could allow the detection of this crater. Hence, it will be interesting to compare LRO high resolution images (NAC images with their resolution of ~1 m on the ground) taken before and after the event. Future studies will be performed to complete our analysis, including the search of the crater, and thus to estimate mass of impact produced dust cloud and the size of exospheric dust particles and to perform hydrodynamic modeling of this event.

Monday, March 2, 2015

In 1969, the United States successfully performed the first human landing on the surface of the Moon. Neil Armstrong and Buzz Aldrin placed an American flag in the lunar surface, winning the space race against the Soviet Union. The US government stated later that no sovereignty claims of any kind were made on the Moon. After that historical breakthrough and for decades to come, space exploration suffered a considerable slowdown. The United States had won the space race, and no serious efforts have since been made by any nation to return to the Moon.

In 1985, researchers at the University of Wisconsin discovered that the lunar soil had a considerable amount of the rare isotope of helium known as helium-3 (He-3). This scarce element could be used in energy production, in fusion power plants that—hypothetically—could produce an amount equivalent to 130,000,000 barrels of oil per ton of He-3.1 . It is also environmentally friendly, producing no greenhouse gases or radiation.

Whether because of helium-3 or not, several nations have recently shown interest in returning to the Moon. In 2013, China became the third country to land a spacecraft on the Moon, and other nations have places for lunar missions in the next several years. Besides nations, several private corporations had expressed interest in lunar missions of one kind or another.

Law in this area is not particularly broad. Nevertheless, during the Cold War and because of the progress in the field of space exploration in those early years, some international treaties related to the legal status of the Moon and the outer space region arose, creating a legal regime that is still valid today. Those treaties are the Outer Space Treaty (1967) and the Moon Treaty (1979), currently the existing legal framework valid to some extent.

These treaties, while overlapping to some degree, settled a series of principles regarding human activities outside Earth. The Outer Space Treaty forbids the placement of weapons of mass destruction in space; it also addressed the situation of lunar sovereignty, claiming that the celestial bodies could not be subject of national appropriation. The later Moon Treaty established that the Moon shall be regarded as common heritage of mankind, in a similar regime as the one applicable to the Deep Sea Bed Area.

This essay will address primarily the legal status of the Moon, using the existing framework on the subject. Taking into account the current state of space exploration and other legal systems similar to the one of the Moon, such as the Deep Sea Bed Area, it will analyse the question of whether the Moon could be considered the Common Heritage of Mankind, or if some other legal concept should be used in relation to its resources.

Friday, February 27, 2015

"Crotts' new book, titled The New Moon: Water, Exploration, and Future Habitation, explores his innovative ideas and many more in meticulous detail, providing hard scientific findings that topple decades-old ideas about the moon's development and structure. Readers may well wonder why the U.S. abandoned its lunar exploration program in 2010, just as so many discoveries were emerging.

"Today, we know that billions of tons of water exist on the moon in the form of ice, and Crotts is sure that more will be found. It's not likely the kind of H2O earthlings drink but rather one rich in heavy water—or deuterium oxide—a form of water in which the hydrogen atom's nucleus is double the mass of ordinary hydrogen, rendering it undrinkable by humans without processing.

"Crotts believes the moon's water could be broken down into liquid hydrogen and liquid oxygen, a potent mix that makes an ultra-efficient form of rocket fuel, the same kind that powered the NASA Saturn V rockets that boosted the Apollo spaceships out of Earth's atmosphere towards the moon.

"You'd have to look hard to find another propellant that's as efficient or better," said Crotts. The moon also has carbon monoxide that Crotts said could be converted with water into methane, another efficient and powerful rocket fuel.

"With all that potential rocket fuel, Crotts naturally believes that the moon could one day be transformed into an interplanetary gas station for the satellites and rockets that today get discarded because they eventually run out of fuel and drift into the wrong orbit."

Wednesday, February 25, 2015

Until the original tapes were found, stored in an abandoned McDonalds Restaurant on site at Ames Research Center, and subsequently read and remastered using totally unavailable equipment built from scratch, this represents our best view of of the rugged slopes of the central peaks of Copernicus crater, a facsimile of a photograph developed in lunar orbit and radioed back to Earth from Lunar Orbiter V, August 17, 1967. For comparison, see the photographs that follow below [USGS].

The Lunar Orbiter Image Recovery Project (LOIRP) is a public/private project to recover, from the original master tapes, the image data from the five spacecraft NASA sent to the moon in the 1960’s and provide it to the scientific community and the public. The first is done through a peer review process and then the data is provided to the National Space Science Data Center (NSSDC) for archiving. We also have a public website through NASA at the Solar System Exploration Research Virtual Institute (SSERVI) at the NASA Ames Research Center. This missive is to explain the background of the mission, the character of the data, and why it is important to our scientific and national history.

At this time we have completed over 90% of the work necessary to archive and publish these images. However, sometimes that last 10% is the hardest and we have in the dozens of terabytes of data to complete the processing of our image captures. Why doesn't NASA pay for this? They have paid for the vast majority of our work. NASA’s Space Science Mission Directorate, NASA Ames, and and SSERVI have been magnificent in support of our work. However, NASA’s budget is severely constrained, and for legacy projects like this, it is our work in technoarchaeology (literally the archaeology of technology) that is saving this data for posterity.

Field of view captured in by Lunar Orbiter V in 1967, shown in the image further above, outlined on a more recent photographic survey by the Lunar Reconnaissance Orbiter (LRO), LROC M181302109R, spacecraft orbit 11832, January 15, 2012 [NASA/GSFC/Arizona State University].

When we started this project, it was only to save the images of Lunar Orbiter’s II and III. However, in 2011 NASA asked us how much it would cost to complete all five orbiters. We estimated $400,000. NASA provided $300,000 of this, leaving a gap of $100,000. This is why we ask for your support in our crowdfunding effort, to complete this task. These images, provided on the SSERVI website, will be free to the public with no copyright. The American taxpayer paid for this effort and even though our company has also contributed materially to the effort and we are extending this through your generous donations through crowdfunding, we want this to be provided free of charge, or any intellectual property right restrictions.

Detail from LOIRP Lunar Orbiter V (Image 151-H1 -Copernicus Central Uplift) The LOIRP Image was derived from the original analog tapes from the LO ground stations and has 4x the dynamic range of the LO film archive. This image with a resolution of about 2 meters, taken on August 16, 1967 from 103 km. This version of the LO-V-151-H image is from the original ground station tape from the Woomera ground station in Australia (tape W5-58).

NASA had stored these original analog data tapes for over four decades, but if it were not for our project and former NASA archivist Nancy Evan’s preservation of the tape drives in her barn, this archive at its best quality would be lost to history. Following is a description of the Lunar Orbiters, their camera, the images and what we are doing to preserve this legacy of the early Apollo program.

Background on the Lunar Orbiter

In 1966-67 NASA sent five spacecraft to the Moon to do a high resolution photo reconnaissance of the surface in preparation for the manned Apollo lunar landings. This was the first time in human history, other than a few closeups before impact from the Ranger spacecraft, that the moon had been seen up close and personal.

Tuesday, February 24, 2015

The combined strategy utilizes the Astrobotic "Griffin" lander (carrying their "Red Rover," in foreground) to deploy a total of three robotic rovers, including the Hakuto "Tetris" and "Moonraker" [Astrobotic/CM].

Angela Moscaritolo

PC

Two rivals battling it out in Google's $30 million competition to land a private spacecraft on the moon are teaming up for a joint trip to the lunar surface.

Hakuto, the only Japanese team competing in Google's Lunar XPrize competition, and Pittsburgh-based Astrobotic on Monday announced they are partnering for a moon journey during the second half of 2016.

The plan is that Hakuto's twin rovers — dubbed "Moonraker" and "Tetris" — will "piggyback" on Astrobotic's so-called "Griffin" lander to reach the moon.

Hatuto sub-rover Tetris [Tim Stevens/C|NET].

Astrobotic will launch the mission next year on a SpaceX Falcon 9 rocket from Cape Canaveral, Fla. After touching down, Hakuto's rovers will be simultaneously released alongside Astrobotic's "Andy" rover, developed by Carnegie Mellon University.

On the evening of 23 March 1983, President Ronald Reagan addressed the people of the United States from the Oval Office. Citing aggressive moves on the part of the Soviet Union, he defended proposed increases in U.S. military spending and the introduction of new missiles and bombers. He then called for a revolution in U.S. strategic doctrine:

Let me share with you a vision of the future. . .What if free people could live secure in the knowledge that their security did not rest upon the threat of instant U.S. retaliation to deter a Soviet attack, that we could intercept and destroy strategic ballistic missiles before they reached our own soil or that of our allies? I know this is a formidable technical task, one that may not be accomplished before the end of this century. . .I call upon the scientific community in our country, those who gave us nuclear weapons, to turn their great talents now to the cause of Mankind and world peace, to give us the means of rendering these nuclear weapons impotent and obsolete.

Thus was born the Strategic Defense Initiative (SDI), which is perhaps better known by its cinema-inspired nickname “Star Wars.” This post is not meant to discuss the geopolitical ramifications or technical feasibility of SDI. It will instead focus on a lesser-known aspect of SDI planning.

Sunday, February 22, 2015

Ron Finkle and a primary exhibit in his remarkable home-based museum of the Apollo program, between Waco and Austin in Texas [Michael Miller | FME News Service]

Deborah McKeon

FME News Service

Killeen Daily Herald

Belton — Ron Finkle grew up during the Apollo era, a time in history he said he’s pretty sure won’t ever be repeated.

Finkle’s fascination with space exploration inspired him to create a small aviation museum in his home consisting of scale models he built and had commissioned, as well as autographs.

A centerpiece of that museum is now a lunar roving vehicle model that Finkle designed and built.

Although many scale-model companies re-created the command module, the crew’s quarters and flight control section, the service module for propulsion and spacecraft support systems, none has recreated an authentic-looking land rover, Finkle said.

The lunar roving vehicle allowed astronauts to travel farther on the moon’s surface during the last three missions of the Apollo program, according to the National Aeronautics and Space Administration.

Finkle spent about six months from start to finish on the land rover, revising it seven times and tweaking it each time, he said.

Daniel Tagtow with Innovate, a product development company based in Austin, created the computer designs, coming up with the specifications for the scale model. Those figures were approved by Finkle and sent to Stratasys Direct Manufacturing, a 3-D printing company in Belton.

Saturday, February 21, 2015

Students at two Hawaii schools have teamed up with NASA to develop lunar dust mitigation experiments which may be tested on Google Lunar X-Prize contestant landers in the near future [HawaiiNewsNow].

Lisa Kubota

HawaiiNewsNow

Students at two Hawaii schools are embarking on a new space mission. They're teaming up with NASA on an experiment that is heading to the moon. Students at Iolani School and Kealakehe High School have been working on the lunar project for months now. NASA developed the electrodynamic dust shield (EDS) to repel pesky planetary dust that gathers on space gear. The technology, which uses electricity to clear off surfaces, hasn't been tested yet in space.

"The dust on the moon is very sharp and scratchy so during NASA's Apollo experience they found that the astronauts were coming back with visors that they basically couldn't see out of because it had gotten so dusted up and scratched up when they tried to wipe them off," explained Iolani teacher Gilson Killhour.

The project involves NASA, the two schools, the Pacific International Space Center for Exploration Systems (PISCES) and a Google Lunar X-PRIZE team. Each campus built a mockup lander and designed a frame for the dust shield.

"It's a very unique opportunity that's probably a once-in-a-lifetime thing and I'm glad I was able to jump on it and be able to participate," said Iolani senior Keegan McCrary.

"If they do make it to the moon, they'll test their own test for Google and then they'll test ours, which is the EDS. They'll have the rover, which is back there, and it will circle around and video," said Iolani senior Veronica Shei.

The students will test their experiment at a PISCES site high atop Mauna Kea next month.

Laser altimetry map of the Moon's northern polar region, north of 80° at 20 meters resolution. The crater Lovelace (57.06 km; 82.08°N, 250.49°E), referenced below, is southwest of Hermite, where the lowest temperatures yet recorded in the Solar System have been measured on the pole-facing walls, in permanent shadow [NASA/GSFC].

Introduction: The possibility of lunar polar ice was suggested by Harold Urey in the 1950's [1], and has likely been directly detected at the North Pole of Mercury by MESSENGER. That detection was based on the presence of reflectance anomalies seen by the Mercury Laser Altimeter (MLA) that occurred only where models of the surface temperature allow long-duration preservation of surface water ice against sublimation [2,3].

Anomalous reflectance is also seen at the lunar poles, revealed by laser measurements. The reflectance of permanently shadowed regions is systematically higher than nearby areas that receive at least some illumination [2,3,4] (Fig. 1). Models suggest that if the higher reflectance is due to the presence of water ice; up to 14 wt.% could be present depending on the distribution of frost within or on the regolith.

Figure 1. DIVINER maximum temperature (left) and LOLA reflectance (right) for the north polar crater Lovelace. The blue patch in the temperature image shows the location of a permanently shadowed region. The corresponding location in the reflectance image clearly show higher reflectance than the surroundings

Results of lunar observations by the Deep Impact High-Resolution Instrument – Infrared spectrometer (HRI-IR) in the 3 μm region and by the Lunar Reconnaissance Orbiter (LRO) Lyman Alpha mapping project (LAMP) in the far-UV region both show that spectral features consistent with hydration of the surface are diurnally variable. This indicates that water is pos-sibly mobile on the lunar surface [5,6]. Because the lifetime of water molecules in the lunar atmosphere is short against dissociation (~20 hours) compared to the lunar diurnal cycle, water must be continuously pro-duced to account for the observations. Mobile water will trap on cold surfaces during the lunar night and be released when surfaces are illuminated during the day.

In this study, we seek evidence for transient water frost on the polar surfaces using reflectance data from the Lunar Orbiter Laser Altimeter (LOLA), and temperature data from the DIVINER radiometer, both onboard the LRO. We aim to search for areas that may “load” with surface frost during the night causing in-creased reflectance, and unload during the day reducing the reflectance. Detection of transient surface frost constrains the rate of input into the lunar volatile system.

Methods and datasets: LOLA measures the backscattered energy of the returning altimetric laser pulse at 1064 nm. This data is used to map the reflectivity of the Moon at zero-phase angle with a photo-metrically uniform data set. The zero-phase geometry is insensitive to lunar topography and enables the characterization of subtle variations in lunar albedo, even at high latitudes where such measurements are not possible with the Sun as the illumination source. The DIVINER radiometer simultaneously measures the bolometric temperature of the lunar surface.

To find evidence of transient surface frost, we examined locations where reflectance data from LOLA exists at both low (less than 156 K, a loss of 100 μm of frost per month or less, sufficiently cold for ice to persist during a single lunar night [7,8]) and high temperatures (greater than 201 K, a loss of 1 mm of frost per month or more, no possibility of retaining surface ice [7,8]) using the DIVINER radiometer data, seeking changes in albedo with temperature. We search the LOLA reflectance dataset for locations that have reflectances measured at both low and high temperatures using DIVINER tem-perature measurements obtained simultaneously with LOLA data. For this initial search, we examined both polar regions at a spatial resolution of 2 pixels per degree (~15 km per pixel), within ±50-90º latitude.

Initial Results: For both polar regions (±50-90º latitude), we find that most of the pixels outside permanently shadowed regions are subject to both low (less than 156 K) and high (greater than 201 K) temperatures. Figure 2 shows the LOLA reflectance data for both poles when the temperature of a given pixel is either greater than 156 K (Fig. 2 left) or greater than 201 K (Fig. 2, right).

Methods and datasets: LOLA measures the backscattered energy of the returning altimetric laser pulse at 1064 nm. This data is used to map the reflectivity of the Moon at zero-phase angle with a photo-metrically uniform data set. The zero-phase geometry is insensitive to lunar topography and enables the characterization of subtle variations in lunar albedo, even at high latitudes where such measurements are not possible with the Sun as the illumination source. The DIVINER radiometer simultaneously measures the bolometric temperature of the lunar surface.

By subtracting the 1064 nm reflectance when the temperature is high (greater than 201 K) from the reflectance when the temperature is low (below 156 K), we find that the global difference in reflectance averages near 0 for both polar regions (Fig. 3). Therefore, we do not detect a general temperature dependent reflectance variation.

Figure 2. LOLA 1064 nm reflectance for (A) the North Pole and (B) the South Pole. The reflectance when the temperature is low (less than 156°K) is shown on the left and the reflectance when the temperature is high (greater than 201°K) is shown on the right.

Figure 3. LOLA 1064 nm reflectance difference between the reflectance when the temperature is high (greater than 201° K) and when the temperature is low (less than 156° K), for (A) the North Pole and (B) the South Pole.

Discussion and future work: We did not detect a general temperature dependent reflectance variation in our study for either polar region with a detection precision of about 1%. Using a simple model of a nonabsorbing layer over an absorbing substrate, a very small optical depth is required to raise the reflectance by 1%, only 0.045 ([9] Section 9.D.2). This corresponds to ~30 μg/cm2, a layer thickness of about 300 nm. In comparison, the observations of [5,6] require a layer thickness of at least 10's of nanometer to account for the observed band depths. This suggests that our current measurements are at the edge of detection of the source implied by the spacecraft observations. In contrast to the implications of the reported measurements, the solar wind can provide far less water; concentrated in a single layer, calculations by [10] suggest only 0.01 nm globally averaged per month.

Our current analysis did not take into account how long each surface element has been subject to cold temperatures (i.e., if it had time to accumulate frost). For example, based on a Monte Carlo model, Schorghofer (2014) [11] showed that a continuous source of water molecules arriving on the lunar surface (regardless of the source) would significantly accumulate near the morning terminator. Additional calculations show that the morning terminator should feature about 30 times the concentration of the average nightside abundance, improving prospects for detection.

Future work includes reanalyzing existing data to include the time of exposure at low temperatures, and conducting targeted observations with LOLA to observe night time polar surfaces near the morning terminator in order to improve the upper limits of detection on transient water frost.

Acknowledgments: This work is supported in part by the LRO LOLA experiment (David Smith PI), the LRO Diviner experiment (David Paige PI), and the Natural Science and Engineering Council of Canada (NSERC).

Figure 1. Top: Lunar albedo proton yield map (cylindrical projection) with anomalous yield regions labeled “A” through “E”. Regions A (Mare Serenitatis) and B (Oceanus Procellarum) are both centered near the boundaries of mare regions. Regions C, D and E are all in the highlands on the far side of the Moon. Bottom: Visible global composite image from the Lunar Reconnaissance Orbiter Camera (LROC).

Introduction: Since the launch of the Lunar Reconnaissance Orbiter (LRO) in 2009, the Cosmic Ray Telescope for the Effects of Radiation (CRaTER) has been mapping albedo protons (~100 MeV) coming from the Moon [1,2].

These protons are produced by nuclear spallation, a consequence of galactic cosmic ray (GCR) bombardment of the lunar regolith. Just as spalled neutrons and gamma rays reveal elemental abundances in the lunar regolith [3-6], albedo protons may be a complimentary method for mapping compositional variations across the Moon’s surface.

Albedo Proton Yield: The CRaTER instrument simultaneously detects albedo protons from the Moon and GCRs arriving from the zenith direction. We divide the number of albedo protons observed over each point on the Moon by the number of GCRs detected over the same location to produce a map of the yield of albedo protons.

We presently find that the lunar maria have an average proton yield which is 0.9% ± 0.3% higher than the average yield in the highlands; this is consistent with some neutron data that shows a similar yield dichotomy due to differences in the average atomic weight between mare regolith and highland regolith [7].

Map Features: There are cases where two or more adjacent pixels (15° × 15°) in the map have significantly anomalous yields above or below the mean.

These include two high-yielding regions in the maria, and three low-yielding regions in the far-side highlands. Some of the regions could be artifacts of Poisson noise, but for completeness we consider possible effects from compositional anomalies in the lunar regolith, including pyroclastic flows, antipodes of fresh craters, and so-called "red spots" which are associated with volcanic domes. We also consider man-made landers and crash sites that may have brought elements not normally found in the lunar regolith.